Had any of the Queensland child safety officers tasked with looking after an abused toddler done their job in the weeks before his horrific death, he may still be alive, a coroner says.
Mason Jet Lee died after he was struck in the abdomen by his mother's boyfriend so hard it ruptured his small intestine, which led to an infection.
The blow was one of many serious and painful injuries the neglected 22-month-old suffered in the months before his death in June 2016.
Deputy state coroner Jane Bentley says the child safety department's handling of Mason's case was "a failure in nearly every possible way".
More than 20 departmental staff, who were investigated following his death, were found to have acted unsatisfactorily.
Their behaviour reflected the failure of the system as a whole, Ms Bentley said in inquest findings handed down on Tuesday.
She also warned that details about Mason's last days would be distressing.
"I include it in the findings not to shock or upset, but in recognition of the fact that these things happened to this little boy whilst he was a child in our community," she told Brisbane Coroners Court.
An autopsy found Mason's death was caused by an infection from internal injuries similar to those seen after car accidents.
He had dozens of other injuries, including a fractured coccyx, extensive bruising and torn skin around his anus.
Mason's declining health in his final days was largely ignored by his mother, Anne-Maree Lee, and stepfather, William O'Sullivan, who are both serving jail sentences for his manslaughter.
The family had been known to the child safety department since before Mason's birth in 2014.
It was also aware of O'Sullivan's "pathological jealousy" and drug use, along with the fact he previously threatened to "skin his wife" and kill his children when they separated.
Mason was hospitalised in early 2016 with injuries a veteran pediatrician described to the inquest as the worst he had seen.
Despite this and the involvement of the police, the department again made the decision to release the toddler back to his family.
In the months before Mason died, child safety officers saw Mason only once for about five minutes in mid-March.
They were required to carry out 12 face-to-face and 12 support contacts with the toddler, Ms Bentley said.
"Had anyone from the department seen Mason in the weeks before his death they could have saved his life."
Ms Bentley said it was difficult to find any steps that complied with the department's policies and procedures, or were correctly documented.
"The fact that the (ethical standards unit) found that 21 employees of the department involved in Mason's case ... failed to carry out their duties appropriately is indicative of the scale of the failure."
Ms Bentley made six recommendations, including that the department reviews its policies about how it implements out-of-home care for at-risk children, and provides information to police.
She also advised Queensland Health to allow doctors to escalate child safety cases when they disagree with a decision made by the department.
Child Safety Minister Di Farmer said the child protection system was a difficult and challenging system and she would consider the coroner's recommendations.
"We take a call about a child potentially at risk of harm every four minutes," she said.
"(But) nobody could possibly read the report that was handed down today and not feel sick to the stomach, to not imagine what that little boy's life was like."
Ms Farmer said three independent reviews had been held into the department since Mason's death, with significant failings identified.
She said an additional $200 million and more than 200 staff had been allocated to address the issues.
Australian Associated Press